My code doesn't seem to work following an upgrade. But I would like to point the following additional use case to the site admins.
USE CASE: Proving someone agreed to the terms and conditions
Each event has terms and conditions. But if you needed to provide in a court of law, that an attendee agreed to a set of conditions, just how would you do that given that the terms and conditions can be arbitrarily changed? The best way is to have a copy of the actual mail sent -- and a feature to cc or bcc an email of the user's choosing would do just that.
So if you weren't convinced before, I hope this will convince you to add this much needed feature.